U.S. patent application number 14/282556 was filed with the patent office on 2014-11-27 for power semiconductor module with liquid cooling.
The applicant listed for this patent is Infineon Technologies AG. Invention is credited to Thorsten Fath, Andre Uhlemann.
Application Number | 20140347818 14/282556 |
Document ID | / |
Family ID | 51863190 |
Filed Date | 2014-11-27 |
United States Patent
Application |
20140347818 |
Kind Code |
A1 |
Uhlemann; Andre ; et
al. |
November 27, 2014 |
Power Semiconductor Module with Liquid Cooling
Abstract
A power semiconductor module includes a substrate and a two-part
cooling system arranged under the substrate. The cooling system has
upper and lower pieces. The upper piece forms a flow channel with
the substrate for a cooling liquid. The upper piece has a first
inflow and an outflow, through which the cooling liquid can be
introduced into the flow channel and removed. The upper piece also
has at least one second inflow, which is spaced apart from the
first inflow in a longitudinal direction. The lower piece has an
inlet and an outlet, the outlet being connected to the outflow and
the inlet being connected to the first inflow. The lower piece also
has a channel branching off from the inlet, which includes at least
one bypass channel, which is connected to the second inflow, so
part of the cooling liquid passes through the bypass channel into
the flow channel.
Inventors: |
Uhlemann; Andre; (Dortmund,
DE) ; Fath; Thorsten; (Warstein, DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Infineon Technologies AG |
Neubiberg |
|
DE |
|
|
Family ID: |
51863190 |
Appl. No.: |
14/282556 |
Filed: |
May 20, 2014 |
Current U.S.
Class: |
361/699 ;
29/25.01 |
Current CPC
Class: |
H01L 23/3672 20130101;
H01L 23/473 20130101; H01L 2924/00 20130101; H02M 7/003 20130101;
H01L 2924/0002 20130101; H01L 2924/0002 20130101; H05K 7/20927
20130101 |
Class at
Publication: |
361/699 ;
29/25.01 |
International
Class: |
H05K 7/20 20060101
H05K007/20; H02M 7/00 20060101 H02M007/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 24, 2013 |
DE |
102013209719.0 |
Claims
1. A power semiconductor module, comprising: a baseplate; a
substrate arranged on the baseplate; and a two-part cooling system
arranged under the baseplate and comprising: an upper piece that
forms a flow channel with the baseplate for a cooling liquid, the
upper piece having a first inflow and an outflow through which the
cooling liquid can be introduced into the flow channel and removed,
the upper piece further having at least one second inflow spaced
apart from the first inflow in a longitudinal direction; and a
lower piece having an inlet and an outlet, the outlet being
connected to the outflow of the upper piece and the inlet being
connected to the first inflow of the upper piece, the lower piece
further having a channel branching off from the inlet, which has at
least one bypass channel, which is connected to the second inflow,
so part of the cooling liquid passes through the bypass channel
into the flow channel.
2. The power semiconductor module of claim 1, wherein the direction
of flow of the cooling liquid runs from the inlet to the outlet in
the longitudinal direction of the module.
3. The power semiconductor module of claim 1, wherein at least one
power semiconductor to be cooled is applied to the substrate.
4. The power semiconductor module of claim 1, wherein the substrate
and the baseplate are formed in one piece.
5. The power semiconductor module of claim 1, wherein cooling ribs
underneath the baseplate protrude into the channel at points to be
cooled and are immersed in the cooling liquid.
6. The power semiconductor module of claim 1, wherein the two-part
cooling system is produced from a single part.
7. The power semiconductor module of claim 1, wherein the baseplate
comprises ceramic or metal.
8. A power semiconductor module, comprising: a substrate to be
cooled; and a two-part cooling system arranged under the substrate
and comprising: an upper piece that forms a flow channel with the
substrate for a cooling liquid, the upper piece having a first
inflow and an outflow through which the cooling liquid can be
introduced into the flow channel and removed, the upper piece
further having at least one second inflow spaced apart from the
first inflow in a longitudinal direction; and a lower piece having
an inlet and an outlet, the outlet being connected to the outflow
of the upper piece and the inlet being connected to the first
inflow of the upper piece, the lower piece further having a channel
branching off from the inlet, which has at least one bypass
channel, which is connected to the second inflow, so part of the
cooling liquid passes through the bypass channel into the flow
channel.
9. The power semiconductor module of claim 8, wherein the substrate
comprises a ceramic.
10. The power semiconductor module of claim 8, wherein the
substrate is a DCB (direct copper bonded) substrate.
11. A method of assembling a power semiconductor module, the method
comprising: arranging a substrate on a baseplate; and arranging a
two-part cooling system having an upper piece and a lower piece
under the baseplate so that: the upper piece forms a flow channel
with the baseplate for a cooling liquid, the upper piece having a
first inflow and an outflow through which the cooling liquid can be
introduced into the flow channel and removed, the upper piece
further having at least one second inflow spaced apart from the
first inflow in a longitudinal direction; and an outlet of the
lower piece is connected to the outflow of the upper piece and an
inlet of the lower piece is connected to the first inflow of the
upper piece, the lower piece having a channel branching off from
the inlet, which has at least one bypass channel, which is
connected to the second inflow, so part of the cooling liquid
passes through the bypass channel into the flow channel.
Description
PRIORITY CLAIM
[0001] This application claims priority to German Patent
Application No. 10 201 3 209 719.0, filed on 24 May 2013, the
content of said German application incorporated herein by reference
in its entirety.
TECHNICAL FIELD
[0002] The present application relates to the area of electronic
cooling, in particular a power semiconductor module with liquid
cooling.
BACKGROUND
[0003] When operating under high currents and voltages,
semiconductor modules, and in particular power semiconductor
modules, generate heat, which reduces the performance and lifetime
of those modules if it is not removed appropriately. In the case of
power semiconductor components and modules, with correspondingly
high power losses, liquid cooling is used to ensure that the heat
is transported away adequately.
[0004] In the case of direct liquid cooling, the power
semiconductor module has on its underside heat exchangers (for
example heat sinks), which take up the heat of the components and,
by direct contact with the cooling liquid, transfer it to the
liquid. Consequently, the cooling liquid heats up while it flows
along the underside of the module, the temperature of the cooling
liquid increasingly becoming closer to the operating temperature of
the module. However, the cooling effect (i.e. the heat transfer
from the module to the cooling liquid) is strongly dependent on the
temperature difference between the component and the cooling
liquid, and consequently the module is cooled better on that side
on which the (cold) cooling liquid flows in than on that side on
which the (heated) cooling liquid flows out again. The components
that are arranged one behind the other in the module (seen in the
direction of flow of the cooling liquid) are accordingly not cooled
uniformly, and therefore experience different thermal loading,
which restricts the lifetime of the module as a whole to the
lifetime of the component that is cooled the worst.
[0005] Previous cooling solutions have only provided longitudinal
and transverse flows of the cooling liquid underneath the
baseplate, longitudinal flows running along the (long) longitudinal
direction and transverse flows running along the (short) transverse
direction of the module. In the case of the longitudinal flow, the
effect of the inhomogeneity of the temperature distribution in the
cooling liquid is at a maximum, since the cooling liquid is
introduced on a narrow side of the module and is carried away again
on the opposite side of the module. Over the entire length (i.e.
along the longitudinal sides) of the module, the cooling liquid
accordingly heats up, whereby the components that are located on
each side of the module on which the heated cooling liquid is
carried away are cooled with warmer liquid than those on the
opposite side of the module, on which the cold cooling liquid is
introduced.
[0006] The solution using transverse flow solves the problem of
inhomogeneity, but requires much greater volumetric flows of the
cooling liquid, since the flow cross section is dictated by the
(long) longitudinal side. The associated higher pumping rates are
unwanted, especially in modern areas of application such as
electric or hybrid vehicles.
SUMMARY
[0007] Embodiments described herein provide a cooling device for a
power semiconductor module with which it is ensured that the heat
is uniformly transported away from the module even with moderate
volumetric flows.
[0008] A power semiconductor module according to a first exemplary
embodiment comprises a baseplate, at least one substrate to be
cooled that has been applied to the baseplate and a two-part
cooling system, arranged under the baseplate. This cooling system
has an upper piece and a lower piece. The upper piece is designed
in such a way that it forms with the baseplate a flow channel for a
cooling liquid, the upper piece having a first inflow and also an
outflow, through which the cooling liquid can be introduced into
the flow channel and removed. Moreover, the upper piece has at
least one second inflow, which is spaced apart from the first
inflow in the longitudinal direction. The lower piece is configured
with an inlet and an outlet, the outlet being connected to the
outflow and the inlet being connected to the first inflow.
Moreover, the lower piece has a channel branching off from the
inlet, which includes at least one bypass channel, which is
connected to the second inflow, and so part of the cooling liquid
passes through the bypass channel into the flow channel.
[0009] A power semiconductor module according to a further
exemplary embodiment comprises a substrate to be cooled and a
two-part cooling system, arranged under the substrate. This cooling
system has an upper piece and a lower piece. The upper piece is
designed in such a way that it forms with the substrate a flow
channel for a cooling liquid, the upper piece having a first inflow
and also an outflow, through which the cooling liquid can be
introduced into the flow channel and removed. Moreover, the upper
piece has at least one second inflow, which is spaced apart from
the first inflow in the longitudinal direction. The lower piece is
configured with an inlet and an outlet, the outlet being connected
to the outflow and the inlet being connected to the first inflow.
Moreover, the lower piece has a channel branching off from the
inlet, which includes at least one bypass channel, which is
connected to the second inflow, and so part of the cooling liquid
passes through the bypass channel into the flow channel.
[0010] Those skilled in the art will recognize additional features
and advantages upon reading the following detailed description, and
upon viewing the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The elements of the drawings are not necessarily to scale
relative to each other. Like reference numerals designate
corresponding similar parts. The features of the various
illustrated embodiments can be combined unless they exclude each
other. Embodiments are depicted in the drawings and are detailed in
the description which follows.
[0012] FIG. 1 illustrates a power semiconductor module in plan
view, the module being made up of three substrates each with eight
power semiconductors, a baseplate and also a cooling system.
[0013] FIG. 2 illustrates a horizontal longitudinal sectional view
of a power semiconductor module according to FIG. 1, the possible
routes of the channels in the cooling system being indicated.
[0014] FIG. 3 corresponds to the representation from FIG. 2, but
the module and the cooling system are shown assembled.
DETAILED DESCRIPTION
[0015] In the following more detailed description, reference is
made to the accompanying figures, in which specific exemplary
embodiments are shown for purposes of illustration. It goes without
saying that, unless otherwise specified, the features of the
various exemplary embodiments described herein may be combined with
one another.
[0016] FIG. 1 shows a power semiconductor module 50 in plan view
from above, comprising of a baseplate 1, a cooling system 2
arranged thereunder and also substrates 3, which have been applied
to the baseplate 1 and on which there may be power semiconductor
components 6. The power semiconductor module 50 is normally
rectangular, and consequently has a longer side (referred to
hereinafter as the longitudinal side) and a shorter side (referred
to hereinafter as the transverse side). Indications of direction
are correspondingly given as the longitudinal direction and
transverse direction. The geometrical shape of the semiconductor
module may also be square. In this case, the longitudinal side and
the transverse side would be of the same length. To facilitate the
description, here, however, a non-square embodiment is described as
an example.
[0017] Unlike as shown in the example from FIG. 1, a substrate 3
may itself assume the function of the baseplates. In this case,
reference is often also made to "baseplateless" modules. For the
purposes of the present description, the "baseplate" is either a
separate baseplate of the module (usually of metal), on which one
or more substrates (usually of ceramic, for example a DCB--Direct
Copper Bonded--substrate) can be arranged, or the (for example
ceramic) substrate itself, on which the semiconductor components
are then arranged directly. The baseplate 1 may preferably have
clearances in the regions between the substrates 3, where no
cooling is necessary. These clearances allow material to be saved
and the pressure loss in the cooling structures to be lowered.
Generally, the clearances are not necessary for the functioning of
the cooling system 2, and therefore represent an optional
configuration.
[0018] The cooling system 2 is only schematically indicated in FIG.
1, in order to illustrate its positioning.
[0019] FIG. 2 shows a horizontal sectional view in the longitudinal
direction of the power semiconductor module 50. The complete module
substantially comprises three main components. Together with the
cooling ribs 7 arranged underneath the regions of the baseplate 1
to be cooled, a baseplate 1, a substrate 3 and the power
semiconductor components 6 arranged on it form the module 100 to be
cooled. The embodiment of the module 100 to be cooled in FIGS. 2
and 3 shows a baseplate 1 of a composite form, which comprises two
different layers. The upper layer (top layer) consists in this case
of copper (Cu), the lower layer consists of aluminum (Al).
Generally, however, the baseplate 1 may also be produced from solid
material (for example Al, AlSiC or Cu). Production processes for
producing such baseplates are, for example, cold extrusion or metal
injection molding (MIM). Arranged on the underside of the module
100 to be cooled is the cooling system 200, which substantially
comprises two components.
[0020] The cooling system 200 therefore comprises two parts. The
upper piece 200', which is connected directly to the underside of
the module 100, and also the lower piece 200'', which lies against
the upper piece 200'. The upper piece 200' has in this case an
upper side which contains a well-like opening, which is configured
in such a way that it forms with the module 100 to be cooled a flow
channel 9 for the cooling medium. In this case, the opening is
configured in a way that the cooling structures (cooling ribs 7)
are completely accommodated in the flow channel 9.
[0021] The upper piece 200' also has an inflow 10 and an outflow 11
to and from the flow channel 9, which, from the lower side of the
piece 200', connect the well-like opening of the upper side to the
lower side. Consequently, cooling liquid can be introduced through
the inflow 10 from the underside of the piece 200' into the flow
channel 9 and flow away again on the other side in the longitudinal
direction through the outflow 11. Apart from the inflow 10 and the
outflow 11, the upper piece 200' has at least one further inflow 8,
which is spaced apart from the inflow 10 and the outflow 11 in the
longitudinal direction (in the direction of flow), and consequently
is thus located between the inflow 10 and the outflow 11 in the
longitudinal direction. In this case, the exact position of the
further inflow 8 is chosen such that it is located between two
cooling structures (cooling ribs 7) in the longitudinal direction.
In the present example, two further inflows 8 are provided in
addition to the inflow 10. Via these inflows 8 and 10, "fresh"
(i.e. cold) cooling medium can be introduced at different points in
the direction of flow (longitudinal direction) of the well-like
opening. The individual inflows 8, 10 are in this case arranged in
such a way that fresh cooling medium can flow directly onto those
regions of the baseplate 1 that are located directly under a heat
source (for example DCB substrate 3 with power semiconductor
components 6, see FIG. 1). Directly flowed onto means in this
connection that the cooling medium reaches the regions to be cooled
of the baseplate 1 underneath a heat source without previously
having been preheated appreciably by neighboring heat sources. An
additional advantage of the bypass cooling system is the much lower
pressure drop in comparison with a standard cooling system, on
account of the lower volumetric flow through the flow channel
9.
[0022] The lower piece 200'' also has an inlet 12 and an outlet 13,
which connect the supply line and removal line of the cooling
liquid to the upper side of the lower piece 200''. In this case,
the inlet 12 and the outlet 13 are configured in such a way that,
when the lower piece 200'' is attached to the upper piece 200' (for
example by adhesive bonding or screwing), the inlet 12 is connected
to the inflow 10 and the outflow 11 is connected to the outlet 13,
and so cooling liquid can flow from the inlet 12 through the inflow
10 into the flow channel 9 and can subsequently flow away out from
the outlet 13 through the outflow 11.
[0023] Moreover, the lower piece 200'' has a channel 14 branching
off from the inlet, which has at least one bypass channel 15, which
is connected to the further inflow 8 of the upper piece 200', and
so part of the cooling liquid flows parallel to the flow channel 9
in the branching channel 14, until it passes through the bypass
channel 15 into the flow channel 9. In this way, fresh (i.e. cold
and not yet preheated) cooling water is injected into the flow
channel 9 at a position closer to the outlet in the longitudinal
direction than the inlet, which provides more effective cooling of
the cooling structure (cooling ribs 7) located there in comparison
with injection into the flow channel 9 via the inflow 10 alone. The
representation in FIG. 3 corresponds to the representation from
FIG. 2, in FIG. 3 the power semiconductor module and the cooling
system being shown assembled.
[0024] Spatially relative terms such as "under", "below", "lower",
"over", "upper" and the like, are used for ease of description to
explain the positioning of one element relative to a second
element. These terms are intended to encompass different
orientations of the device in addition to different orientations
than those depicted in the figures. Further, terms such as "first",
"second", and the like, are also used to describe various elements,
regions, sections, etc. and are also not intended to be limiting.
Like terms refer to like elements throughout the description.
[0025] As used herein, the terms "having", "containing",
"including", "comprising" and the like are open-ended terms that
indicate the presence of stated elements or features, but do not
preclude additional elements or features. The articles "a", "an"
and "the" are intended to include the plural as well as the
singular, unless the context clearly indicates otherwise.
[0026] With the above range of variations and applications in mind,
it should be understood that the present invention is not limited
by the foregoing description, nor is it limited by the accompanying
drawings. Instead, the present invention is limited only by the
following claims and their legal equivalents.
* * * * *